Brake cylinder device



March 28, 1950 A. J. BENT A BRAKE CYLINDER DEVICE Original Filed July31, 1947 m a v l ||J l.. i 1 n l l n.1... nlflllillfl|Il:ullllllitlllnlilllnlllllllllllnlfrlllll ATTORNEY Patented Mar. 28,1950 BRAKE CYLINDER DEVICE Arthur J. Bent, Pittsburgh, Pa., assigner toThe Westinghouse Air Brake Company, Wilmerding, Pa., a corporation ofPennsylvania Original application July 31V, 1947, Serial No.

1948, Serial No. 36,847

4 Claims.

This invention relates to fluid pressure brake cylinder devices and moreparticularly to brake cylinder devices for use with variable load brakeequipment comprising fluid pressure actuated slack adjuster means. Thisapplication is a division of my copending application, Serial No.764,941, led July 31, 1947.

It is a prime object of the invention to provide an improved uidpressure brake cylinder device 'comprising slack adjuster control meansfor use in variable load brake equipment.

Other objects and advantages will be apparent from the following moredetailed description of the invention,

In the accompanying drawing, the single figure is a diagrammaticsectional View taken longitudinally through a brake cylinder deviceembodying the invention.

As shown in the drawing, the improved brake cylinder device comprises ahollow cylindrical casing I which may be cast of aluminum to reduce itsweight to a minimum commensurate with strength, and which is closed atone end by a preferably integral pressure head 2. To the open end of thecasing l is secured an annular pressure head 3 interposed between saidcasing and a cup-shaped non-pressure head 4 which are secured togetherby bolts (not shown). The heads 3 and t also are preferably formed ofaluminum to reduce their Weight. A brake cylinder piston assemblage 5 isslidably mounted in the casing I, and at one side thereof is the usualor a main pressure chamber 6 to which is connected a pipe 'I by way ofregistering passages 8 extending through removable fittings 9 and I0 andcentrally through the pressure head 2. The pipe I is adapted to beconnected in turn to a fluid pressure control valve device (not shown),such as the'Well-known AB valve, to eiect variations in pressure offluid in the pressure chamber 6 for controlling and operating pistonassemblage 5.

The piston assemblage 5 comprises a piston head II which may be formedof drawn steel to reduce to a minimum the -amount of machine worknecessary to 4form it. This head is provided with a circular flatcentral portion and an annular portion encircling the flat centralportion which annular portion is in the form of a portion of a sphere.An annular peripheral groove I2 is machined in the head Il for securinga resilient snap-on packing cup I3, disposed in the chamber 6, to oneface of said head. The packing cup I3 is provided with an annularU-shaped portion I4, which portion is open to chamber 6 and which curvesinto slidable conor the like.

Divided and this application July 3,

tact with the inner wall of the casing in such a manner that pressure offluid in said chamber acts thereon to urge it into sealing engagementwith said wall for preventing leakage of fluid under pressure past thepiston head. An annular substantially U-shaped metal ring I5 isinterposed between the portion I4 of the packing cup I3 and one face ofa radially projecting annular flange I6 attached to the piston head H. Aportion of the ring I5 is curved to form a support for the back ofportion It of cup I3. A lubricating swab II, in the form of a felt orsimilar ring encased in an expander ring, is disposed within the ring I5and thereby secured to move with the piston head II in slldable contactwith the casing wall to distribute and store lubricant thereon for aconsiderable period of time. The outer peripheral edge of the flange ISattached to the piston head II is machined to provide an accurate fitfor slidable contact between said head and the casing wall.

A hollow cylindrical member I8, disposed on the opposite side of thepiston head I I, is secured adjacent its one end to said head formovement therewith by an annular baille member I9, and

is slidably guided at its opposite end by a sleeve member 20 disposed inand secured to the nonpressure head The annular baffle member I9 issecured at its outer periphery by a continuous Weld ZI, or othersuitable means, to a face of the flange IE of the piston head Il, andthe member I8, which projects through the member I9, is secured to theinner peripheral edge of said member I9 by means of a similar continuousWeld 22,

The member I9 for the major portion of its width is dished in thedirection toward the piston, head II for the purpose of impartingrigidity to said member.

An annular compensating pressure chamber 23 is defined by the outercylindrical surface of member I8 and the inner surface of casing Ibetween the annular baiile member I9 and the annular pressure head 3.The chamber 23 is connected to a pipe 2t by way of registering passages-25 in the pressure head 3, the non-pressure head 4 and a removablefitting 26. The pipe 24 is adapted to be connected to a novel relayvalve device (not shown), described in the aforementioned copendingapplication, for eiecting variations in the pressure of uid in thechamber 23 in accordance with the degree of loading on the vehicle.Pressure of fluid in the chamber 23 acts on the annular area of thebaiiie member i9, secured to the piston head II, in opposition to theforce on said head caused by the pressure of fluid in the usual pressurechamber 3, and since the pressure in said chamber 23 is varied in themanner as above described. the effective force delivered by said headfor applying the brakes varies in accordance with the degree of loading.The welds 2i and 22 acting to secure member I3 to member I9, and memberI9 to piston head II serve also to form a seal for preventing fluidunder pressure from escaping from the compensating pressure chamber 23past the baille member I9. A resilient annular sealing ring 21 isdisposed in a groove in the pressure head 3 for slidable engagement withthe outer surface of member I8 to prevent leakage of fluid underpressure from chamber 23 past said head.

The sleeve member 23 is provided at one end with.an outwardly projectingannular flange 23 which is disposed coaxially with relation to themember I3 in a central counter-bore 29 in the non-pressure head 4. Thiscounter-bore provides a shoulder against which the flange 2B rests. Anannular ring member 3l is pressed into the counter-bore 23, which memberabuts the flange 23, holding said flange rigidly seated against theshoulder 30, thereby removablv securing the sleeve member 20 to the head4. A lubricating swab 32 in the form of an annular felt ring is mountedin a groove in member 3| for slidable engagement with the outer surfaceof the member I3.

The sealing ring '21 is provided with an outer flat edge portion whichis clamped between the heads 3 and 4 to allow for easy removal andinsertion and an inner edge portion 33 is made U- shaped in crosssection, similar to portion I4 of cup I3. The portion 33 opens in thedirection ofthe chamber 23 so that action of pressure of fluid thereinurges the ring 21 into sealing engagement with the member I3.

The interior of the hollow cylindrical sleeve member I3 forms anon-pressure chamber 34 which opens into the interior of thenon-pressure head 4. The non-pressure chamber 34 is constanth7 open toatmosphere through a breather port 35 in head 4 covered by an airstraine1 3'? of curled hair or the like. The strainer 36 is disposed inan open cup-shaped retainer 31 secured to the head 4 and encircling theport 35. 'I'he port 35 is provided to permit free passage of air intoand out oi' the non-pressurel chamber 34 upon recfprocation of thepiston head II in the casing I, while the strainer over said port isadapted to prevent dust and dirt from entering said chamber. Thestrainer 34 is preferahlv mounted at the lower side of the non-pressurehead 4 in order to avoid. insofar as possible. free entrance of dirt andmoisture to said strainer.

A base member 33 is disposed within the nonpressure chamber 34 adjacentto the piston head II. A hollow piston rod 33. of the usual type. issecured at its one end by means oi' rivets to a boss 40 attached fo themember 33. The opposite end of the rod 39 extends through and isslidahlv guided within a tapered opening 4I in an end wall 42 in thenon-pressure head 4. A push rod 43 DrOiectS into the rod I3 in the usualmanner and` abuts a steel insert 44 carried by the aluminum base member33.

Thel base member 33 is arranged to mnv with the piston head I I fortransmitting thrust tn the push rod 43. and thence to the brak. rimfinvfor annlvina the brakes (not shown). Clearance is provided between theouter periphery of the ha n member 33 and the inner wall of the memberI3 so that as said base moves with the piston head [lll I I it is freeto adjust itself in a radial direction to correct for any initialmisalignment with the piston II and the member I3 and thereby preventhinding. The tapered opening 4I in the wall 42 allows the piston rod 33attached to the base member 33 the necessary freedom for suchadjustment.

The face of the base member 33 is provided with an annular curvedsurface 45, which may be in thc shape of a portion of a. sphere, forslidable engagement with the corresponding curved surface of the pistonhead II. The central portion of the member 33 encircled by the annularcurved surface 45 is provided with a cavity 43 of larger diameter thanthe diameter of the central flat portion oi the piston head II so thatthe surface 45 is allowed freedom for travel on said head II to providefor the previously described radial adjustment.

A retaining member 41 in the form of a thin hollow cylinder isspot-welded to the inner wall of the cylindrical member I3. The member41 is provided with a plurality of spaced-apart thin vieldablc fingers43 which are deflned by longitudinally extending slots cut in the member41. The fingers 48 are bent into engagement with the member 33 and actto hold said member and piston head II together during removal of thecasing I from the non-pressure head 4. For example, if inspection of thepacking cup I3 is desired, the casing I is unbolted from thenon-pressure head 4 and said casing is slipped off over the pistonassemblage 5 to expose said packing cup. A retaining ring 43 in theusual form, secured to the outer end of piston rod 39 prevents themember 3B from moving in the direction of the left-hand, as viewed inthe drawing, and the retainer member 41 comprising the flngers 43anchors the member I3 and attached piston head II to said base member 33to prevent them from moving with the casing.

The fingers 43 are flexible so that. whereas they are of sufficientstrength to serve to anchor the piston head II to the base member 33.they 1 yield to allow said base to move radially during the previouslydescribed aligning adjustment. One end of a compression return spring5'! seats on the flexible fingers 43, urging said fingers into contactwith the member 33 and. in turnl ureing said member into contact withthe piston Yhead II, so that once said member has moved to an adjustedposition with respect to said niston head it will be held in theadjusted position bv friction and the yieldable clamping action of thespring and fln'gers, it being understod that the structure isat alltimes automatically adjustable to prevent any bending action on themovable parts of the piston assemblage.

The compression return spring 53 is provided to serve the usual purposeof returning the piston assemblage 5 to its normal brake releasedposition, as shown in the drawing, in effecting the release of a brakeapplication. The spring 53 is disposed in the non-pressure chamber 34encircling the piston rod 39 and is tapered to prevent it from cockingas it is further compressed during travel of the piston assemblage 5.VThe opposite end of the spring 53 seats on an annular seat flange 5Iattached to a sleeve 32 which is slidably mounted on the piston rod 39.An annular V-shaped resilient porous filter member 53 encircles the rod39 and is interposed between a beveled face of the flange 5I and abeveled shoulder 54 formed in the end wall 42 encircling the taperedopening 4I in the non-pressure head 4.

The filter member 53 is squeezed, by action of the spring 58, betweenthe ange 5| and shoulder 54 into contact with the outer surface of thepiston rod 39 and with the portion of wall 42 encircling the opening 4Iso that any air entering through said opening which may be carrying dustor dirt must pass through the member 53 and thereby be filtered orcleaned.

The brake cylinder device is provided with a pressure indicator 55 whichindicates at all times whether or not there is fluid under pressurepresent in the compensating pressure chamber 23 for thereby enabling aninspector of the brake equip-k ment, at any time, to determine visuallywhether or not the brake equipment is adjusted for an empty or loadedcar.

According to a feature of the invention the improved brake cylinderdevice is further provided with a slack-adjuster control valve device 18which comprises a casing 1I mounted on the nonpressure head 4 andcovering a relatively large opening 12 in said head which opens into thenon-pressure chamber 34. The casing 1I is provided with a fluid pressuresupply passage 13 connected to a iiuid pressure pipe 14. which pipe isin turn connected to the passage 8 in the fitting Ill secured to endwall 2 of the casing I to thereby act as a communication for supply ofiiuid under pressure to said supply passage 13. The casing 1I is alsoprovided with a fluid pressure delivery passage 15 which is adapted b vmeans of a tting 16 to be connected to a pipe 11 for connection with afiuid pressure actuated slack adjuster device (not shown) of the usualfluid pressure controlled type. A bore 18 is formed in casing 1| whichextends between respective ends of passages 13 and 15. A valve seatbushing 19 is provided which has a press fit with the bore 18. Thebushing is provided with a through bore 80 extending longitudinallytherethrough between a delivery chamber 8|, formed in said bore, and thenon-pressure chamber 34 in the head 4. The chamber 8| is closed at itsone end by a removable cap 82 secured by screw threads to casing 1 I Asupply valve 83 is disposed in delivery chamber 8| and is attached to asleeve member 84 which is sldably mounted in the bore 88. A compressionspring 85 is arranged to urge the valve 83 to a normally closed positionseated on an annular shoulder formed in the seat bushing 19encirclineing the end of bore 88. An annular groove is formed in theouter periphery of the bushing 19, which groove registers with the endof the supply passage 13 and is constantly open to ports 86 connected toan annular chamber within the bore 88.

The annular chamber is formed by a groove in the member 84, so thatfluid under pressure from the passage 13 will fiow to the deliverychamber 8|, thence t0 the passage 15 and the pipe 11 when the valve 83is unseated. A central bore extends through both the valve 83 and thesleeve 84 between the delivery chamber 8| and the chamber 34 in the head4. A release valve 81,-attached to a uted stem slidably mounted in thebushing 84, is disposed in the chamber 34 for opening and closing thedelivery chamber 8| to the chamber 34 via the bore in the sleeve 84 tocontrol release of uid under pressure from the pipe 11. An actuating arm88 is pivotally attached to the casing 1I for actuating the valves 83and 81. A compression return spring 89 is arranged to bias the arm 88away from the valve 81 with which valve said arm remains in contact. Ashoulder 98 is formed in the casing 1I against which the arm 88 abuts todeiine a normal rest position projecting into the chamber 34 and intothe path of travel of the hollow cylindrical member I8. The arm 88 is solocated that overtravel of the piston assemblage 5, caused by overtravelof the brake rigging due to wear of the brake shoes, permits the memberI8 to move into engagement with the arm 88 and thereby displaces thearm, in opposition of action of the spring 89, to first seat the releasevalve 81 on the sleeve 84 and, by movement of said sleeve, to unseat thesupply valve 83 to supply fluid under pressure to the pipe 11 foractuating the slack adjuster. During the release of the brakes, as thepiston assemblage 5 including the member I8 return to rest positions, asshown in the drawings, said member I8 moves away from the arm 88 andallows the springs 85 brake rigging to maintain travel of the -brakecylinder piston substantially constant to compensate for the eiect ofbrake shoe wear which tends to increase said travel.

Since the welds 2| and 22 serve to secure the baffle member I9 to thepiston head II and the cylindrical member I8 to said baffle, as well asserve to seal oiie the compensating pressure chamber 23 encircling themember I8 from the nonpressure chamber within said member I8, said weldsmay be pressure tested to prove their sealing qualities. It will beappreciated that means other than welding, such as brazing or solderingmight be employed to serve the same purpose.

The sealing ring 21 cooperating with the outer wall of cylindricalmember I8 is protected from excessive Wear due to abrasive action ofdust and dirt by virtue of its location within the brake cylinder deviceinto which nol dust laden air is allowed to flow, either directly or`indirectly. The ring 21 is further protected from excessive wear byvirtue of-its cooperation with the member I8, which remains entirelyenclosed within the casing of the brake cylinder device at all times andis not subjected to corrosive action of the elements, consequently themember- I8 presents clean smooth surface for slidable sealing contactwith said ring.

While only one illustrative embodiment of the invention has been shownand described in detail, it is not my intention to limit its scope tothat embodiment or otherwise than by the terms of the appended claims.

- Having nowdescribed my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. A fluid pressure brake cylinder device comprising a hollowcylindrical casing closed at one end by a first pressure head, anon-pressure head secured to said casing, an annular pressure headinterposed between said casing and said non-pressure head, a piston headslidably mounted in said casing and dening a first fluid pressurechamber at one side thereof adjacent to said first pressure head, afirst fluid pressure conduit for communicating uid under pressure to andfrom said first pressure chamber, an annular baflie member secured atits outer periphery to said piston head to form a sealed jointtherewith, a hollow cylinder member secured to the 7 inner periphery ofsaid baille member to form a sealed joint therewith and projecting intosaid annular pressure head, said cylinder member serving to define anannular compensating pressure chamber between said baille member andsaid annular pressure head and a non-pressure chamber opening into saidnon-pressure head, a second iiuid pressure conduit for communicatingiiuid under pressure to and from said annular pressure chamber, aresilient sealing ring clamped betwen said annular pressure head andsaid nonpressure head for slidable sealing engagement with the outerwall of said cylinder member, a sleeve member secured to and disposed inthe non-pressure head for slidably and guidably supporting said cylindermember, a base member disposed in said non-pressure chamber and abuttingsaid piston head, a compression, piston return spring disposed in saidnon-pressure chamber and seating at one end on said base member tooppose movement of said piston head in the direction of saidnon-pressure chamber, a hollow piston rod secured to said base memberand extending through an opening in said non-pressure head, normallyclosed fluid pressure valve means mounted on said non-pressure head,said valve means having a iluid pressure supply conduit and a iiuidpressure delivery conduit and being operative to open said deliveryconduit to said supply conduit, lever means disposed in the path oftravel of said cylinder member for operating said valve means, and meanssensitive to pressure of fluid in said compensating pressure chamber forindicating pressure of uid therein.

2. A brake cylinder device comprising a hollow cylindrical casing havinga pressure head at one end, a non-pressure head secured to theopposite'end, a piston in said casing cooperative with said pressurehead to deilne a pressure chamber at one side of said piston forreceiving iluid under pressure ,to move said piston in the direction ofsaid non-pressure head, means for conducting iluid under pressure to andfrom said pressure chamber, a tubular member projecting from theopposite side of said piston and movable therewith, a control valvedevice assoelated with said non-pressure head, and means operable bysaid member to actuate said valve device upon a chosen movement of saidmember and piston by pressure of iiuid in said pressure chamber.

3. A brake cylinder device comprising a hollow cylindrical casing havinga pressure head at one end, a non-pressure head secured to the oppositeend, a piston in said casing cooperative with said pressure head todeilne a pressure chamber at one side of said piston for receiving iluidunder pressure to move said piston in' the direction of saidnon-pressure head, means for conducting fluid under pressure to and fromsaid pressure chamber, a tubular member projecting from the oppositeside of said piston and movable therewith, a control valve deviceassociated with said non-pressure head, said control valve device havinga fluid pressure inlet chamber, a iluid pressure outlet chamber, and avalve for controlling communication between said inlet and outletchambers, a pipe connecting said inlet chamber to said pressure chamber,and means operable by said member to open said valve upon a chosenmovement of said member and piston by pressure of uid in said pressurechamber.

4. A brake cylinder device comprising a hollow cylindrical casing, apressure head closing one end oi' said casing, a non-pressure headsecured to the opposite end of said casing, a second pressure headclamped between said non-pressure head and said opposite end of saidcasing, a

piston slidably mounted in said casing cooperative with said casing andthe first named pressure head to deiine one pressure chamber at one sideof said piston, a tubular member projecting from the opposite side ofsaid piston through said second pressure head into said nonpressurechamber and cooperative therewith and with said casing to form acompensating pressure chamber, means for supplying iluid under pressureto and releasing iluid under pressure from said pressure chambers, acontrol device associated with said non-pressure head for supplyingfluid under pressure from said one pressure chamber to a controlpassage, and means operable by said tubular member to actuate saidcontrol device in a chosen position of said piston away from the rstnamed pressure head.

ARTHUR J. BENT.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date '137,985 White Sept. 1, 1903821,870 'Hildebrand May 29, 1906

